Dynamic coordination of protection devices in electrical distribution systems

ABSTRACT

A dynamically coordinatable electrical distribution system includes a plurality of intelligently-controlled protection devices (PDs), a communication and control bus (comm/control) bus, and a central computer. The plurality of intelligently-controlled PDs is configured to protect a plurality of associated electrical loads from faults, developing faults, and other undesired electrical anomalies. Each of the PDs further has electrically adjustable time-current characteristics. The intelligently-controlled PDs are communicatively coupled to the comm/control bus and configured to report current data representative of real-time currents flowing through their respective loads to the central computer, via the comm/control bus. The central computer is configured to communicate with the plurality of PDs over the comm/control bus and dynamically coordinate the time-current characteristics of the plurality of PDs based on the current data it receives from the PDs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/076,304, filed on Mar. 21, 2016, and claims the benefit of U.S.Provisional Patent Application No. 62/143,299, filed on Apr. 6, 2015 andU.S. Provisional Patent Application No. 62/301,948, filed on Mar. 1,2016.

FIELD OF THE INVENTION

The present invention relates to electrical distribution systems,protection devices used in electrical distribution systems, and methodsand apparatus for dynamically coordinating time-current characteristicsof protections devices in electrical distribution systems.

BACKGROUND OF THE INVENTION

Electrical distribution systems distribute electrical power from anelectrical power transmission system to electrical power consumers. Toprotect and isolate electrical loads from abnormal operating conditionsand allow electricians and engineers to safely work on and maintain anelectrical distribution system, circuit breakers are deployed at variousstages in the distribution system. For example, circuit breakerscomprise part of the switchgear that is installed within powerdistribution stations and substations and are installed in panelboardsat or near service drops of commercial buildings and residences.

A principal function of a circuit breaker is to protect its load and theelectrical conductors in the load circuit from overcurrent conditions.In general, there are two types of overcurrent conditions: an “overload”and a “fault.” The National Electrical Code (NEC) defines an “overload”as: “operation of equipment in excess of normal, full-load rating, or aconductor in excess of rated ampacity that when it persists for asufficient length of time, would cause damage or dangerous overheating.”A “fault” is defined as “an electrical connection, which is madeunintentionally, resulting in an excessive amount of overcurrent.”Faults typically produce much higher currents than do overloads,depending on the fault impedance. A fault with no impedance is referredto as a “short circuit” or a “bolted fault.”

FIG. 1 is a simplified one-line drawing of a typical electricaldistribution system 100, illustrating how conventional circuit breakersare deployed in the distribution system. Alternating current (AC) powersupplied from the secondary winding of a step-down transformer 102 isconnected to a first set of circuit breakers within a main distributionpanel (MDP) 104. The first set of circuit breakers in the MDP 104includes a main circuit breaker, which provides short-circuit andoverload protection to all downstream loads in the system. The remainingcircuit breakers in the MDP 104 serve to provide fault and overloadprotection to loads that are either directly connected to the MDP 104,such as motor load 106, or to one or more sub-panelboards 108, whichinclude “downstream” circuit breakers (and possibly othersub-panelboards) that provide fault and overload protection toadditional loads, such as motor load 110 and light load 112.

Conventional circuit breakers have been in widespread use for manyyears. However, there are various challenges and drawbacks relating totheir use. One problem relates to the precision, both in terms of timeand current, at which they are capable of responding to faults and otherovercurrent conditions and the uncertainty that results due to theirlack of precision. Conventional circuit breakers are electromechanicalin nature and typically use some sort of spring mechanism to controlwhether line current is allowed to flow into their load circuits.Unfortunately, due to limitations on the magnetics and mechanical designinvolved, the time it takes, and the current level at which, aconventional circuit breaker trips in response to a fault can vary, evenfor a circuit breaker that is selected from a group of breakers havingthe same type and rating, and even among several circuit breakers of thesame type and rating provided by the same manufacturer. The time-currentprecision of a conventional circuit breaker also tends to degrade anddeviate over time, due to aging of its electromechanical components.Because of this variability, circuit breaker manufactures will oftenprovide time-current characteristic data for each type and rating ofcircuit breaker that they manufacture. The time-current characteristicdata of the circuit breaker is typically displayed in a two-dimensionallogarithmic plot, such as illustrated in FIG. 2, with current on thehorizontal axis, time on the vertical axis, and “tripped” and “nottripped” regions separated by an uncertainty band within which the tripstatus of the circuit breaker is uncertain.

In an effort to address the time-current uncertainties of conventionalcircuit breakers, electricians and engineers will often perform what isknown as a “selective coordination study” when designing an electricaldistribution system. The selective coordination study is usuallyperformed prior to the electrical distribution system being constructed.The goal of the selective coordination study is to select and mapcircuit breakers in the distribution system design so that only theclosest circuit breaker upstream from a fault or overload condition willtrip in response to a fault or overload condition. A successfulselective coordination study will help to ensure that only thosesections of the electrical distribution system that are downstream fromthe source of the fault or overload condition are isolated andde-energized, allowing the remaining upstream sections of thedistribution system to continue operating, despite the fault or overloadcondition.

A selective coordination study is performed taking into considerationthe time-current characteristic data provided by the circuit breakermanufacturers. During the study, circuit breakers of different types andamperage ratings are selected and mapped into the design with the goalof preventing the uncertainty bands of the various circuit breakers fromoverlapping. Overlapping bands is undesirable since it provides anindication that one or more upstream circuit breakers may unwantedly orprematurely trip in response to a fault or overload condition, insteadof a downstream breaker that is closer to the source of the fault oroverload condition and which could otherwise fully isolate the fault oroverload condition on its own.

There are software tools available in the prior art that display theuncertainty bands of the various mapped circuit breakers and which canassist electricians and engineers in performing selective coordinationstudies. Unfortunately, due to the uncertainty bands present in thetime-current characteristics of the various mapped circuit breakers, theelectrician or engineer will often determine that it is not possible toprevent one or more of the uncertainty bands from overlapping, asillustrated in FIG. 3. In order to address this problem, the circuitbreakers must be rearranged and/or replaced with circuit breakers ofdifferent types and/or ratings.

Not only are selective coordination studies cumbersome to perform andtime-consuming, they are also prone to error, particularly since humaninterpretation is involved. For example, when electrical generators andinduction motors are part of the system design, assumptions must be madeas to how current from such loads might possibly be injected into afault when a fault occurs. Those assumptions are not always accurate,and the errors that follow, along with other errors that can take placein the selective coordination study, can be unwittingly translated intothe actual construction of the electrical distribution system. Moreover,once a selective coordination study has been completed and the study isimplemented in hardware, in practice, little adjustment can be made,except for replacing circuit breakers with other types of circuitbreakers. Some conventional circuit breakers include mechanicaladjustments, which allow the time-current characteristics of the circuitbreakers to be manually adjusted once they have been installed. However,those adjustments are often inadequate at preventing the time-currentuncertainty bands of the various circuit breakers from overlapping andupstream breakers end up tripping prematurely or unnecessarily, causinga larger portion of the distribution system to be de-energized than isnecessary.

BRIEF SUMMARY OF THE INVENTION

Methods, systems and apparatus for dynamically coordinating thetime-current characteristics of a plurality of intelligently-controlledprotection devices (PDs) in an electrical distribution system aredisclosed. An exemplary dynamically coordinatable electricaldistribution system includes a plurality of intelligently-controlledPDs, a communication and control bus (comm/control) bus, and a centralcomputer. The plurality of intelligently-controlled PDs is configured toprotect a plurality of associated electrical loads from faults,developing faults, and other undesired electrical anomalies. Each of thePDs further has electrically adjustable time-current characteristics.The intelligently-controlled PDs are communicatively coupled to thecomm/control bus and configured to report current data representative ofreal-time currents flowing through their respective loads to the centralcomputer, via the comm/control bus. The central computer is configuredto communicate with the plurality of PDs over the comm/control bus anddynamically coordinate the time-current characteristics of the pluralityof PDs based on the current data it receives from the PDs.

Further features and advantages of the invention, including a detaileddescription of the above-summarized and other exemplary embodiments ofthe invention, will now be described in detail with respect to theaccompanying drawings, in which like reference numbers are used toindicate identical or functionally similar elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a one-line drawing of a typical electrical distributionsystem, illustrating how conventional circuit breakers are deployed inthe distribution system;

FIG. 2 is a drawing showing the time-current characteristics of aconventional electromechanical circuit breaker;

FIG. 3 is a drawing showing the time-current characteristics of severalconventional electromechanical circuit breaker, highlighting how thetime-current uncertainty bands of the circuit breakers can overlap, evenafter completing a selective coordination study;

FIG. 4 is a one-line drawing of a dynamically coordinatable electricaldistribution system, according to an embodiment of the presentinvention;

FIG. 5 is a drawing that depicts one way in which theintelligently-controlled protection devices (PDs) in the dynamicallycoordinatable electrical distribution system depicted in FIG. 4 can beimplemented, in accordance with one embodiment of the invention;

FIG. 6 is a perspective drawing of the PD depicted in FIG. 5,illustrating how the PD can be housed within an enclosure and showingother aspects, elements and features of the PD;

FIG. 7 is a drawing showing the time-current characteristics of the PDdepicted in FIGS. 5 and 6;

FIG. 8 is a drawing that depicts one way in which the PDs in thedynamically coordinatable electrical distribution system depicted inFIG. 4 can be implemented, in accordance with one embodiment of theinvention;

FIG. 9 is a functional circuit block diagram of the fault detection andresponse circuitry used in the sense and drive circuit of the PD in FIG.8;

FIG. 10 is a drawing of a flowchart that illustrates a method that thefault detection and response circuitry of the sense and drive circuit ofthe PD depicted in FIG. 8 follows in detecting and responding to faultsand developing faults;

FIG. 11 is a drawing that illustrates how the PD depicted in FIG. 8might possibly be modified to produce an intelligently-controlled PDhaving a mechanical or electromechanically-controlled circuit breaker;

FIG. 12 is a perspective drawing of the PD depicted in FIG. 8,illustrating how the PD can be housed within an enclosure and showingother aspects, elements and features of the PD;

FIG. 13 is drawing of an exploded view of the PD depicted in FIG. 8,highlighting the physical attributes of the air-gap disconnect unitincluded in the PD and the various components involved in its operation;

FIG. 14 is a drawing that illustrates how a plurality of PDs like thatdepicted in FIG. 8 can be deployed and configured in a panelboard,according to one embodiment of the invention;

FIG. 15 is a drawing showing the salient elements of the centralcomputer used in the dynamically coordinatable electrical distributionsystem depicted in FIG. 4;

FIG. 16 is a drawing showing the time-current characteristics of a PDlike that depicted in FIG. 8, showing the trip-setting parameterst_(UPPER), t_(LOWER), i_(LT), and i_(MAX) of the PD;

FIG. 17A is a drawing that shows the time-current characteristics offive PDs before being dynamically coordinated;

FIG. 17B is a drawing that shows the time-current characteristics of thesame five PDs depicted in FIG. 17B, after the PDs have been dynamicallycoordinated using the methods and apparatus of the present invention;

FIG. 18 is a drawing of a flowchart that illustrates a method that thecentral computer is programmed to follow in dynamically coordinating aplurality of PDs in an electrical distribution system, in accordancewith one embodiment of the present invention;

FIG. 19 is a drawing that illustrates how the panelboard depicted FIG.14 can be housed within a panel box;

FIG. 20 is drawing depicting a one-line graphical user interface (GUI)page that is displayed on the display of the central computer (in thiscase, a touchscreen display of a tablet computer) and that a user canview and interact with;

FIG. 21 is a drawing depicting a panel GUI page that is displayed on thedisplay of the central computer (in this case, a touchscreen display ofa tablet computer) and that a user can view and interact with;

FIG. 22 is a drawing of a flowchart that illustrates a method that thecentral computer is programmed to follow in allowing the user to updatedisplay information being displayed on the displays of the PDs and thepanel display;

FIG. 23 is a drawing depicting a dynamic coordination GUI page that isdisplayed on the display of the central computer (in this case, atouchscreen display of a tablet computer) and that a user can interactwith to assist in dynamically coordinating a plurality of PDs in anelectrical distribution system; and

FIG. 24 is a drawing of a flowchart that illustrates a method that thecentral computer performs when a user is interacting with the dynamiccoordination GUI page that is displayed on the display of the centralcomputer (in this case, a touchscreen display of a tablet computer) andthat a user can interact with to manually coordinate a plurality of PDsin an electrical distribution system.

DETAILED DESCRIPTION

Referring to FIG. 4, there is shown a one-line drawing of a dynamicallycoordinatable electrical distribution system 400, according to anembodiment of the present invention. The dynamically coordinatableelectrical distribution system 400 may be deployed in the vicinity ofthe service drop of a building (e.g., a residence, or commercialbuilding), as part of the switchgear in an industrial complex orelectrical distribution station or substation, or, in fact, at anystage, section or facility of an electrical power system where agrouping or hierarchy of circuit breakers is desired or necessary tocontrol distribution of power. As illustrated in FIG. 4, the dynamicallycoordinatable electrical distribution system 400 includes a maindistribution panel (MDP) 402 and may further include one or moresub-panelboards 404. The MDP 402 has a service entrance, through whichAC power from an input AC power source, such as may be provided at theoutput of a step-down transformer 406, for example, connects to a powerbus, power cables, or busbars in the MDP 402. (It should be mentionedthat, although in the description that follows an AC electricaldistribution system is assumed, the present invention may also beadapted for use in direct current (DC) electrical distribution systems.)Depending on the application, the input AC power may be 3-phase or1-phase power. A main circuit breaker 408 in the MDP 402 controlswhether the received input AC power can be distributed to the remainderof the system. When the main circuit breaker 408 is OFF (i.e., open) theremainder of the system is de-energized and electrically isolated fromthe input AC power. When the main circuit breaker 408 is ON (i.e.,closed) input AC power is allowed to be distributed to inputs ofintelligently-controlled circuit breakers 410 in the MDP 402. Theseintelligently controlled circuit breakers 410 are referred to as“intelligently-controlled PDs,” “protection devices,” or most succinctlyas “PDs” in the detailed description that follows. The descriptor“intelligently-controlled” is used to highlight the fact that the PDsfunction, and are of a significantly different construction, thanconventional circuit breakers. Note the main circuit breaker 408 mayalso comprise an intelligently controlled PD. Alternatively, it maycomprise a conventional circuit breaker.

As shown in FIG. 4, AC power from the MDP 402 is distributed, via one ormore PDs 410, to one or more directly-connected loads 412 (depicted inthe drawing using black-filled squares) and, if present, to one or moresub-panelboards 404, each of which further includes its ownintelligently-controlled PDs 410 that selectively distribute electricalpower downstream to additional loads 412.

The PDs 410 in the MDP 402 and sub-panelboard(s) 404 of the dynamicallycoordinatable electrical distribution system 400 are further configuredso that they are in electrical communication with a communications andcontrol bus (“comm/control bus”) 414. The comm/control bus 414 maycomprise any suitable bus technology, such as, for example, an inter-IC(I2C) bus or controller area network (CAN) bus. As will be explained infurther detail below, the comm/control bus 414 provides the ability ofthe PDs 410 to communicate with, and to be controlled by, a centralcomputer 416, via a head-end interface 418. The head-end interface 418can be implemented in various ways, depending on the type of comm/bus414 being used and the type of operating system and communicationprotocol used by the central computer 416. In one embodiment of theinvention, the head-end interface 418 includes an adapter or gatewaythat allows the central computer 416 to make a wired connection to thehead-end interface 418, for example, using universal serial bus (USB)technology, Ethernet technology, or other wired connection technology.In another embodiment of the invention, the head-end interface 418includes a wireless transceiver (for example, a Wi-Fi transceiver),which allows a wireless transceiver in the central computer 416 tocommunicate with the comm/control bus 414 and PDs 410 over a wirelesslink. As will be discussed in detail below, among other tasks, thecentral computer 416 serves to analyze current data informationcollected from the PDs 410; compute, set, and adjust, even in real time,the time-current characteristics (e.g., trip current, time-to-trip,and/or amperage ratings) of the various PDs 410; and dynamicallycoordinate the various PDs 410 in the distribution system 400.

FIG. 5 is a drawing that depicts one way in which each of the PDs 410 ofthe dynamically coordinatable electrical distribution system 400 can beimplemented, in accordance with one embodiment of the invention. Theexemplary PD 500 comprises a microcontroller 502, computer-readablemedia (CRM) 504; a solid-state device 506; a current sensor 508; anAC/DC converter 510; user control buttons 512; a visual display 514; anda maintenance disconnect mechanism 516. Depending on the design andapplication, the PD 500 can be a 3-phase device, a 1-phase device, or aDC device. In the case of a 3-phase device, the PD 500 is designed,configured and controlled to measure three current measurements, therebyallowing the system to react to any type of fault, including 3-phase andsingle-line ground faults.

The solid-state device 506 may comprise any suitable controlledsolid-state device, such as a silicon-controlled rectifier (SCR),insulated-gate bipolar transistor (IGBT), powermetal-oxide-semiconductor field-effect transistor (power MOSFET), etc.

The AC/DC converter 510 serves to convert AC power from the input ACline (labeled “Line-IN” in FIG. 5) to DC power for powering themicrocontroller 502 and other DC components in the PD 500. In anotherembodiment of the PD, a separate and dedicated DC power supplyindependent of AC line power is used.

The microcontroller 502 in the exemplary PD 500 includes one or moreinput/output ports that allow the PD 500 to connect to the comm/controlbus 414, thereby allowing the central computer 416 to address, identify,communicate with, and control the PD 500. The microcontroller 502operates according to computer program instructions stored in the PD'sCRM 504. The CRM 504 may comprise nonvolatile memory (e.g., flash-memoryetc.), a magnetic or optical memory, random access memory (RAM) or anycombination of these or other types of computer readable media. The CRM502 may be entirely external to the microcontroller 502 (as depicted inthe FIG. 5) or may be embedded, whole or in part, in the microcontroller502.

The computer program instructions stored in the CRM 504 are addressableby the microcontroller 502 and when fetched and retrieved from the CRM504 direct: how and when the microcontroller 502 produces a GatingDisable signal to turn OFF PD's solid-state device 506 and instructionsand/or commands that direct how and when the microcontroller 502 reportsinformation (e.g., current and voltage information relating to its load)over the comm/control bus 414 to the central computer 416. The computerprogram instructions may further include instructions that allow themicrocontroller 502 to monitor and determine current flow directionthrough the solid-state device 506. With this capability, specificsections of the electrical distribution system that may be at risk ofreverse current flow, for example, as forced by the back-EMF ofinduction motors and field current failures on electrical generators,can be de-energized when necessary.

The computer program instructions stored in the CRM 504 of the PD 500may further include instructions that direct: how and when themicrocontroller 502 reports identification information to the centralcomputer 416 over the comm/control bus 414 (e.g., physical address, PDmodel name and number, fed-from information, and the name and type ofload being protected by the PD 500); how the microcontroller 502responds to activations of the user control buttons 512; and/or how andwhat kind of information is displayed on the PD's display 514 such as,for example, amperage rating of the PD 500, real-time load current andvoltage information, PD name, PD model number, fed-from information,and/or any other real-time or non-real-time information. Preferably, thedisplay 514 comprises an electronic ink display, which is a displaytechnology that allows the information that is being displayed tocontinue to be displayed even after power to the display 514 is removed.

It should be mentioned that whereas in the exemplary embodiment of theinvention described here, each of the various PDs includes its owndedicated microcontroller 502, a single microcontroller ormicroprocessor could be alternatively employed to control a plurality ofthe PDs 500 in a given locale (for example, a plurality of PDs in eachpanelboard).

As shown in FIG. 6, the PD 500 also includes: line connection terminals(Line-IN and Line-OUT) 602 and 604 for connecting the PD 500 to the ACinput and load; a comm/control bus connector 606 that connects the PD500 to the comm/control bus 414; a faceplate 608 with cut-outs forreceiving the user control buttons 512, which may include ON and OFFbuttons 610 (e.g., green-colored ON button and red-colored OFF buttonor, alternatively, red-colored ON button and green-colored OFF button)that power-up and power-down the PD 500 and a RESET button (not shown);indicator lights (for example light-emitting diodes (LEDs) 612, whichpreferably emit light of different colors for indicating the ON, OFF andTRIP status of the PD 500; an optional audible alarm; a cut-out throughwhich the electronic ink display 514 can be viewed; and amaintenance-disconnect tab or latching mechanism 516 that allowselectricians to remove the faceplate 608 so that troubleshooting andmaintenance can be performed. In one embodiment of the invention, themaintenance-disconnect mechanism 516 is designed so that when thefaceplate 608 is removed electrical power is isolated, therebyprotecting electricians and anyone else who may come in contact with thePD 500 with the faceplate 608 removed from electrical hazards, andensuring compliance with lockout/tagout (LOTO) procedures, which may berequired by electrical codes.

Because the PD 500 employs the solid-state device 506, it is able todetect and respond to faults, impending faults and other electricalanomalies much more rapidly than is possible if a conventionalelectromechanical circuit breaker was to be used. The solid-state device506 has the inherent ability to change states (i.e., to be turned ON andOFF) in a matter of microseconds. By employing the solid-state device506, the PD 500 is therefore able to isolate faults and developingfaults over a thousand times faster than is possible using aconventional electromechanical circuit breaker, which typically takeseveral milliseconds to respond to and isolate faults and developingfaults.

In addition to having the ability to isolate faults and developingfaults nearly instantaneously, another significant benefit provided bythe PD 500 is that its time-current characteristics are much moreprecise than are the time-current characteristics of conventionalelectromechanical circuit breakers. Solid-state devices can bemanufactured repeatedly to have nearly identical operatingcharacteristics. This repeatability-in-manufacturing capabilitysignificantly reduces variability from one solid-state device to anotherand, consequently, the variability from one PD 500 to another. Thecurrent conducted by the solid-state device 506 can also be rapidlycontrolled and with a much higher degree of precision than is possiblein conventional electromechanical circuit breakers. These attributesresult in the PD 500 having a time-current characteristic data profilethat is represented by a single line, as illustrated in FIG. 7. Incontrast, and was explained above in reference to FIG. 2, conventionalelectromechanical circuit breakers of the same type and rating, and evenof the same type and rating provided by the same manufacturer, have timeand current characteristics that tend to vary with a high degree ofvariability, resulting in uncertainty bands in their time-currentcharacteristics. (Compare FIG. 7 to FIG. 2.)

FIG. 8 is a drawing depicting another way in which the PDs 410 of thedynamically coordinatable electrical distribution system 400 can beimplemented, in accordance with another embodiment of the invention. ThePD 800 is similar to the PD described in co-pending and commonlyassigned U.S. Patent Application No. 62/301,948, which is incorporatedherein by reference. Like the PD 500 described above in reference toFIGS. 5 and 6, the PD 800 includes a microcontroller 802;computer-readable media (CRM) 804; a solid-state device 806; a currentsensor 808; a DC power source (not shown); user control buttons 810; anda display 814. However, unlike the PD 500, the PD 800 further includes asense and drive circuit 816, which controls the ON/OFF status of thePD's 800's solid-state device 806 (rather than relying on themicrocontroller to perform that task) and an air-gap disconnect unit818, which is connected in series with the solid-state device 806,between the Line-IN terminal and line-in input of the solid-state device806. The various components of the PD 800 operate similar to the PD 500described above, except that the sense and drive circuit 816 is employedto detect the occurrence of faults and developing faults and generatethe Gating Disable signal to turn the solid-state device 806 OFF whenconditions warrant, rather than directly by the microcontroller (as inthe PD 500). Another difference between the PD 500 and the PD 800 isthat the PD 800 includes the air-gap disconnect unit 818, which asexplained in detail below adds an additional level of isolationcapability not provided by the PD 500.

FIG. 9 is a functional circuit block diagram of the fault detection andresponse circuitry 900 used in the sense and drive circuit 816 of the PD800, in accordance with one exemplary embodiment of the invention. Thefault detection and response circuitry 900 comprises: a differentiator402; first, second and third high/low comparators 904, 906, 908; an ANDlogic gate 910; and an OR gate 912. The various electrical components ofthe fault detection and response circuitry 900 are preferably mounted onprinted circuit board (PCB), which may be the same PCB upon which themicrocontroller 802 is included or may be a separate PCB dedicated forthe sense and drive circuit 816.

The fault detection and response circuitry 900 serves to determinewhether a sudden increase in current being drawn by the PD's loadcircuit is due to a load being brought online or is due to a fault ordeveloping fault. This function is important since it avoids thesolid-state device 806 from being turned OFF unnecessarily when thesudden increase in current is due to a load being brought online and notbecause of fault or developing fault. The fault detection and responsecircuitry 900 is also capable of distinguishing between resistive andinductive loads and determining whether a sudden increase in currentcorresponds to an inrush current of an inductive load when being broughtonline or may be the result of a developing fault. FIG. 10 is aflowchart that illustrates a method 1000 that the fault detection andresponse circuitry 900 of the sense and drive circuit 816 follows inperforming these various functions. First, at step 1002, the faultdetection and response circuitry 900 receives a sense current i_(SENSE)from the PD's current sensor 808. The sense current i_(SENSE) representsthe real-time line current being drawn by the load circuit that the PD800 is serving to protect. At decision 1004 the first high/lowcomparator 904 in the fault detection and response circuitry 900determines whether the received sense current i_(SENSE) has exceeded an“instant-trip threshold current” i_(MAX). The instant-trip thresholdcurrent i_(MAX) establishes the absolute maximum current that the PD 800will allow to flow into the load circuit, under any circumstance. If thecurrent being drawn into the PD's load circuit (as represented by thesense current i_(SENSE)) ever exceeds the instant-trip threshold currenti_(MAX), the first high/low comparator 904 produces a logic HIGH output,which after passing through the OR logic gate 912 will quickly turn thePD's solid-state device 806 OFF, as indicated by step 1014 in themethod. The time it takes to turn the solid-state device 806 OFF islimited only by the propagation delay through the first high/lowcomparator 904 and the reaction time of the solid-state device 806 inswitching from an ON state to an OFF state. The word “instant” is usedhere to indicate that this time will be on the order of a fewmicroseconds or even less. Immediately after, or as soon as thesolid-state device 806 is being directed to turn OFF, at step 1016 inthe method 1000 the PD's microcontroller 802 will send an electricalpulse to a solenoid in the air-gap disconnect unit 818 of the PD 800(see FIG. 8). The purpose and function of the air-gap disconnect unit818 will be described in detail below.

It should also be emphasized that the various steps and decisions in themethod 1000 represented in the flowchart in FIG. 10 are not necessarilyperformed in the order shown. Additionally, because various of theoperations performed by the fault detection and response circuitry 900are performed continuously or simultaneously, the various steps anddecisions in the flowchart should not be viewed as necessarily being atimed sequence of events. For example, although decision 1004 appears asa discrete step in a sequence of steps and decisions, decision 1004 isactually performed continuously. So is step 1002 and possibly othersteps and decisions in the method 1000.

The differentiator 902 in the fault detection and response circuitry 900serves to differentiate the sense current i_(SENSE) it receives from thePD's current sensor 808 and produce a differentiated sense currentdi_(SENSE)/dt. This step in the method 1000 is indicated by step 1006 inthe flowchart. The differentiated sense current di_(SENSE)/dt is therate of change of the sense current i_(SENSE) and is used by the faultdetection and response circuitry 900 to determine whether a suddenchange in sense current i_(SENSE) is due to a resistive load beingbrought online or is representative of a developing fault. Because theline current and sense current i_(SENSE) are AC signals, with positiveand negative half cycles, and since a sudden increase in line current(as represented by the sense current i_(SENSE)) can possibly occurduring either positive or negative half cycles, the differentiator 902differentiates both positive and negative half cycles of the sensecurrent i_(SENSE). In this way the fault detection and responsecircuitry 900 can determine whether a fault may be developing duringboth positive and negative half cycles of the line current.

The second and third high/low comparators 906 and 908 and AND logic gate910 are the components of the fault detection and response circuitry 900that determine whether a sudden change in sense current i_(SENSE) is dueto a resistive load being brought online or is representative of adeveloping fault. As alluded to above, the ability to make thisdistinction is important since it avoids the solid-state device 806 ofthe PD 800 from being turned OFF unnecessarily or prematurely in theevent that a sudden increase in current is due to a resistive load beingbrought online and not because of an impending fault. As part of makingthis determination, at decision 1008 in the method 1000, the thirdhigh/low comparator 908 compares the differentiated sense currentdi_(SENSE)/dt to a predetermined maximum rate of change in currentdi/dt_max. If at decision 1008 the differentiated sense currentdi_(SENSE)/dt is determined to exceed the maximum rate of change incurrent di/dt_max, the third high/low comparator 908 produces a logicHIGH output. The logic HIGH output provides an indication that a faultmay be (though not necessarily) developing in the PD's load circuit. Onthe other, if at decision 1008 it is determined that the differentiatedsense current di_(SENSE)/dt is less than the maximum rate of change incurrent di/dt_max, the output of the third high/low comparator 908remains at a logic LOW.

It should be emphasized the fault detection and response circuitry 900will continue to compare the sense current i_(SENSE) to the instant-tripthreshold current i_(MAX) (at decision 1004), regardless of the value ofthe differentiated sense current di_(SENSE)/dt. As explained above, thefirst high/low comparator 904 and OR logic gate 912 will direct thesolid-state device 806 to immediately turn OFF (at step 1014 in theflowchart) if the sense current i_(SENSE) ever rises to a level thatexceeds the instant-trip threshold current i_(MAX). In other words, evenif it is determined that the differentiated sense current di_(SENSE)/dtis less than the maximum rate of change in current di/dt_max at decision1008, the solid-state device 806 will be turned OFF if i_(SENSE) everbecome greater than i_(MAX).

When a resistive load is being brought online, the current that it drawsfrom the line will be step-like. However, a developing fault will alsoproduce a step-like change in current. Since di_(SENSE)/dt is high bothwhen the resistive load is being brought online and when a fault isdeveloping in the PD's load circuit, a di_(SENSE)/dt that exceedsdi/dt_max is not by itself sufficient to conclude whether a resistiveload is being brought online or whether a fault is developing in thePD's load circuit. However, one significant difference between adeveloping fault and the a resistive load being brought online is thatonce the step-like change in current of the resistive load hascompleted, which will happen very quickly, the magnitude of current thatthe resistive load draws will level off to some finite value—thespecific value depending on the resistance of the load. On the otherhand, when a fault is developing, the magnitude of current being drawnfrom the line will rise and continue to rise to a magnitude that islimited only by the ability of the line to deliver current to the fault.The fault detection and response circuitry 900 exploits this differenceby further employing the second high/low comparator 906. Specifically,as indicated by decision 1010 in the flowchart, the second high/lowcomparator 906 compares the magnitude of the sense current i_(SENSE) tothe magnitude of a “long-time trip threshold current” i_(LT). If thecurrent being drawn from the line (as represented by the sense currenti_(SENSE)) rises to a value greater than the long-time trip thresholdcurrent i_(LT), the second high/low comparator 906 produces a logic HIGHoutput. Accordingly, in a situation where both di_(SENSE)/dt exceedsdi/dt_max (a “YES” at decision 1008) AND the current being drawn fromthe line, as represented by the sense current i_(SENSE), exceeds thelong-time trip threshold current i_(LT) (a “YES” at decision 1010), theAND logic gate 910 will generate a logic HIGH output. The logic HIGHoutput is a true indication that a fault is developing in the PD's loadcircuit or that an exceedingly high overload condition is present.Accordingly, once the AND logic gate 910 produces the logic HIGH output,and the logic HIGH output passes through the OR gate 912, a GatingDisable signal is produced at the output of the fault detection andresponse circuitry 900, to quickly turn the solid-state device 806 OFF,as indicated by step 1014 in the flowchart. By turning the solid-statedevice 806 OFF, the developing fault or exceedingly high overloadcondition is quickly isolated. On the other hand, even if at decision1008 it is determined that di_(SENSE)/dt is greater than di/dt_max, solong as it is determined at decision 1010 that the sense currenti_(SENSE) is below the long-time trip threshold current i_(LT), aconclusion is drawn that the sudden change in sense current i_(SENSE)(i.e., high di_(SENSE)/dt) is indicative of a resistive load beingbrought online and the AND logic gate 910 will produce a logic LOWoutput, thereby allowing the solid-state device 806 to remain ON and theresistive load to be brought online.

The fault detection and response circuitry 900 is further capable ofdistinguishing between resistive and inductive loads and protectingagainst exceedingly high inrush currents when an inductive load is beingbrought online. An inductive load will result in a smaller di_(SENSE)/dtwhen being brought online compared to the near step-like di_(SENSE)/dtthat results when a resistive load is being brought online. Accordingly,when the inductive load is being brought online the AND logic gate 910will not produce a logic LOW output, and so long as the sense currenti_(SENSE) remains below the instant-trip threshold current i_(MAX) thefirst high/low comparator 904 will also maintain a logic LOW output asthe inductive load is being brought online. However, if the inrushcurrent that the inductive load is drawing while being brought online(or that it draws under any other circumstance) ever exceeds theinstant-trip threshold current i_(MAX), the first high/low comparator904 will produce a logic HIGH output, which after passing through the ORlogic gate 912, will direct the solid-state device 806 to turn OFF toprotect the inductive load and the load circuit wiring from theexceedingly high inrush current.

The fault detection and response circuitry 900 in FIG. 9 provide anentirely hardware solution for detecting and responding to developingfaults. A hardware solution is preferred since it provides the fastestway to detect and respond to impending faults. In fact, the faultdetection and response circuitry 900 is capable of detecting andisolating developing faults in a matter of a few microseconds, or evenless. While a hardware approach is preferred due to the fast detectionand reaction capability, a ‘software’ approach could be alternativelyused. The PD 500 described above in reference to FIG. 5 is an example ofa software-controlled approach. There, the microcontroller 502 of the PD500 is programmed and configured to detect and respond to developingfaults and the microcontroller generates the Gating Disable that turnsthe solid-state device 506 OFF when conditions warrant.

Although the PD 500 depicted in FIG. 5 and the PD 800 depicted in FIG. 8both utilize a solid-state device to isolate faults and otherundesirable overcurrent conditions, it is possible that either PD (thePD 500 or the PD 800) could be modified so that it utilizes a mechanicalor electromechanical circuit breaker. Although solid-state devices arepreferred, controlling a mechanical or electromechanical circuit breakerusing sense and drive circuit similar to that described above couldpossibly allow the mechanical or electromechanical circuit breaker to becontrolled more rapidly compared to prior art approaches, and couldpossibly eliminate, or perhaps at least reduce to some extent, thetime-current uncertainties associated with mechanical orelectromechanical circuit breakers and/or improve the reaction time andprecision at which those types of circuit breakers operate. FIG. 11 is adrawing that illustrates how the PD 800 might possibly be modified toproduce a PD 1100 having a mechanical or electromechanically-controlledcircuit breaker 1106. The PD 1100 includes a microcontroller 1102programmed to perform functions similar to the microcontroller 802 ofthe PD 800 and a sense and drive circuit 1104 that controls the openingand closing of the mechanical or electromechanically-controlled circuitbreaker 1106.

Like the PD 500 described above in reference to FIGS. 5 and 6, thevarious components of the PD 800 depicted in FIG. 8 are preferablyhoused in an enclosure, such as illustrated in FIG. 12. The enclosureincludes a front face 1202 with cut-outs for the PD's 800's ON and OFFbuttons 810; a cut-out for the electronic ink display 814; and a cut-outfor an air-gap disconnect RESET button 1204, the purpose of which willbe described next.

FIG. 13 is an exploded view of the PD 800 without the electronics(microcontroller 802, sense and drive circuit 816, and solid-statedevice 806) shown. This exploded view of the PD 800 highlights thephysical attributes of the air-gap disconnect unit 818 (see FIG. 8) andthe various components involved in its operation, including the RESETbutton 1204. As shown in the drawing, the PD 800 is housed in anenclosure that includes a front enclosure member 1302, through whichcut-outs for the ON/OFF buttons 810 (see FIG. 12), air-gap disconnectreset button 1204, and display 814 are made; a mid enclosure member1304; and a bottom enclosure member 1306. A solenoid 1308, which formsthe actuating component of the air-gap disconnect unit 818, andassociated holding member 1310 are mounted next to one another on amounting plate 1312, with the holding member 1310 designed to fit underthe L-shaped holders 1314 and the solenoid 1308 mounted alongside onsolenoid mounts 1316. The solenoid 1308 includes a plunger 1318, whichunder normal operating conditions (e.g., in the absence of a fault,developing fault, or other unacceptable overcurrent condition) remainsretracted in the solenoid housing. The holding member 1310 is configuredto slide in a direction parallel to the direction that the plunger 1318travels, and includes a tab 1320 at one end. The tab 1320 has a size anddimensions that allows it to fit inside a slot 1322 formed through acentral section of a connector blade holster 1324. During normaloperating conditions, when power is being distributed to the connectedload and no fault or other undesired overcurrent condition is present ordeveloping in the load circuit, the tab 1320 of the holding member 1310remains positioned in the slot 1322 formed through the connector bladeholster 1324. With the tab 1320 positioned in the slot 1322, the holdingmember 1310 serves to hold electrically conductive male connector blades1326 in corresponding electrically conductive receptacles 1328 of afemale line-to-load connector 1330 and prevent holster retractionsprings 1332 from pulling the connector blade holster 1324 and attachedmale connector blades 1326 out of the receptacles 1328. By holding theelectrically conductive male connector blades 1326 in the electricallyconductive receptacles 1328, line current is allowed to flow to the load(so long as the solid-state device 806 is also ON). However, upon thesense and drive circuit 816 sensing and reporting to the microcontroller802 that a fault or exceedingly high and unacceptable overcurrentcondition is present or developing in the load circuit, themicrocontroller 802 responds by transmitting an electrical pulse to thesolenoid 1308. The electrical pulse causes the solenoid 1308 to ejectits plunger 1318. The holding member 1310 is attached to the plunger1318. Accordingly, when the plunger 1318 is ejected from the solenoidhousing, the tab 1320 of the holding member 1310 is removed from theslot 1322 in the connector blade holster 1324. Once the tab 1320 hasbeen removed from the slot 1322, the retraction springs 1332 are able tolift the connector blade holster 1324, pulling the attached electricallyconductive male connector blades 1326 out of the electrically conductivereceptacles 1328 of the female line-to-load connector 1330. Pulling themale connector blades 1326 out of the receptacles 1328 results in theformation of an air gap, which serves to fully isolate the load fromwhatever fault or other hazard is developing or is present. Because theair gap is in series with the solid-state device 806, the air gap alsoprevents any leakage current that might otherwise flow throughsolid-state device 806 from flowing into the load circuit.

It should be pointed out that the PD 800 depicted in FIG. 8 is anexample of a three-phase PD. Accordingly, there are three male connectorblades 1326 attached to the bottom of the connector blade holster 1324and three corresponding receptacles 1328 formed in the femaleline-to-load connector 1330. In a single-phase PD, only a single maleconnector blade 1326 and corresponding single female receptacle 1328would be needed to create the air gap. It should also be pointed outthat the sense and drive circuit 816 described above in reference toFIG. 8 is an example of a sense and drive circuit 816 designed for usein a single-phase PD. In the case of a three-phase PD, the sense anddrive circuit 816 could be modified for use in a three-phase PD, therebyallowing the modified sense and drive circuit to react to any type offault or undesired overload condition, including three-phase andsingle-line ground faults.

During the air-gap disconnect process the air-gap-disconnect RESETbutton 1204 is forced out of (i.e., pops out of) the front enclosuremember 1302 by a compression spring 1334. The air-gap-disconnect RESETbutton 1204 has a hole 1336, through which a maintenance or serviceworker can insert a padlock or other locking device to complete alockout-tagout (LOTO) safety procedure. Completing the LOTO safetyprocedure ensures that the PD 800 will not be accidentally reset by themaintenance or service worker and will not be inadvertently reset byother persons unaware of the hazard. Once the hazard has been cleared bythe maintenance or service worker, the padlock or other locking devicecan then be removed and the PD 800 can be reset by pressing theair-gap-disconnect RESET button 1204 back into the enclosure. Pushingthe air-gap-disconnect RESET button 1204 back into the enclosure forcesthe electrically conductive male connector blades 1326 to be reinsertedinto the electrically conductive receptacles 1328 of the femaleline-to-load connector 1330 and allows the tab 1320 at the end of theholding member 1310 to be reinserted into the slot 1322 in the connectorblade holster 1324. Note that the solenoid 1308 has an internal springthat pulls the plunger 1318 back into the solenoid housing shortly afterit has been ejected and the air-gap has been formed. Since the holdingmember 1310 is also attached to the plunger 1318, the tab 1320 at theend of the holding member 1310, when the plunger 1318 is pulled backinto the solenoid housing, the holding member 1310 is also pulled backto it normal operating condition position, with the tab 1320 reinsertedback into the slot 1322 of the connector blade holster 1324. With thetab 1320 reinserted back into the slot 1322, the holding member 1310 isthen able to once again hold the male connector blades 1326 in thereceptacles 1328 of the female line-to-load connector 1330 without theretraction springs 1332 pulling the connector blade holster 1324 andattached male connector blades 1326 out of the receptacles 1328. Theholding member 1310 will then continue to hold the male connector blades1326 in the receptacles 1328 until the air-gap disconnect process isonce again activated.

In the description above, the air-gap disconnect process is activatedautomatically upon the sense and drive circuit 816 determining that afault or other potentially harmful overcurrent condition is present ordeveloping in the load circuit. The PD 800 also provides the ability fora person to manually activate the air-gap disconnect process. Thismanual control is provided by the OFF button, which is electricallyconnected to the microcontroller 802. When a person presses the OFFbutton, the microcontroller 802 responds by sending an electrical pulseto the solenoid 1308 to activate the air-gap disconnect process.

It should be pointed out that because the real-time load currentinformation sensed by the currents sensor 808 in the PD 800 is sent tothe PD's microcontroller 802 and not just to the sense and drive circuit816, the air-gap disconnect unit 818 can still be activated even if thesolid-state device 806 should ever fail and even if any component in thefault detection and response circuitry 900 of the sense and drivecircuit 816 ever fails. This ability to activate the air-gap disconnectunit 818 independent of the operational status of the solid-state device806 and independent of the operational status of the fault detection andresponse circuitry 900 provides a “fail-safe.”

FIG. 14 is a drawing that illustrates how a plurality of the PDs 800depicted in FIG. 8 can be deployed and configured in a panelboard 1400,such as, for example, the MDP 402 or one of the sub-panelboards 404 inthe dynamically coordinatable electrical distribution system 400described above in reference to FIG. 4. A power distribution backplanewith busbars and/or other electrical conductors are configured toreceive AC power from the service drop (e.g., 208 to 600 VAC) anddistribute the received AC power to the various PDs 800 in thepanelboard 1400. The PDs 800 then distribute the AC power they receiveto their respective loads and electrically isolate their respectiveloads from the AC power they receive when conditions warrant, in themanner described above. The PDs 800 are also electrically connected tothe network comm/control bus 414, so that they can communicate with andbe controlled by the central computer 416 over the comm/control bus 414,via the head-end interface 418. Note that the head-end interface 418 mayinclude a wired adapter (for example, a USB-CAN bus adapter if thecomm/control bus adapter is a CAN bus) or a USB-comm/bus bus dongle thatallows the central computer 416 to make a wired connection to thehead-end interface 418 and communicate and control the PDs 800 in thepanelboard 1400. Alternatively (or additionally) the central computer416 and head-end interface 418 can be equipped with wirelesstransceivers (e.g., Wi-Fi transceivers), thereby allowing the centralcomputer 416 to communicate with the comm/control bus 414 and PDs 800over a wireless link. The head-end interface 418 may also oralternatively include a wide-area-network capable (WAN-capable) adapterthat allows the central computer 416 to communicate with and control thePDs 800 over a wide area network (WAN), such as the Internet or acellular communications network. With this capability, the centralcomputer 416 can then be situated remotely, if necessary or desired andpossibly controlled by a utility company.

FIG. 15 is a drawing that shows the salient elements of the centralcomputer 416, which may comprise a server, desktop computer, laptopcomputer, tablet computer, smartphone, or any other type of computingdevice. As shown in the drawing, the central computer 416 includes amicroprocessor 1502; computer readable memory (CRM) 1504; an optionalhuman-machine interface (HMI) 1506, through which a user can interactwith central computer 416; an optional display 1508; and a storagedevice 1510 (e.g., a magnetic hard drive or a solid-state drive) thatmay be configured to store, among other things, current and voltageinformation associated with the PDs 410 (e.g., trip-setting parametersfor the PDs 410, historical and/or heuristically-derived time-currentinformation and characteristics of the PDs 414, the electricaldistribution system in which the PDs 414 of the system 400 are deployed,etc.).

The non-transitory CRM 1504 of the central computer 416 is configured tostore computer program instructions that direct how the microprocessor1502 of the central computer 416 operates. These computer programinstructions may include, but are not limited to: instructions thatdirect how and when microprocessor 1502 communicates with the PDs overthe comm/control bus 414, via the head-end interface 418; instructionsthat direct how and when the microprocessor 1502 receives or fetchescurrent and/or voltage information; instructions that control how andwhen the microprocessor analyzes current and/or voltage informationreceived from the PDs and historical and/or heuristic current and/orvoltage information retrieved from storage 1510; instructions thatdirect how the microprocessor 1502 calculates trip-setting parametersfor the PDs to adapt to; and instructions that determine how and when,and under what circumstances, the microprocessor 1502 transmits updatedtrip-setting parameters to the PDs, in order to dynamically coordinatethe PDs in the system 400. Some or all of these operations can beperformed in real time, and in most circumstances without disrupting thegeneral operation of the distribution system 400. The real-timecapability not only affords the ability to adjust, control and optimize,in real time, the trip settings of the PDs, it also completelyeliminates the need for pre-planned or ad hoc selective coordinationstudies. It also allows higher-level zones or sections of thedistribution system 400 that may be operationally important or which maybe susceptible or sensitive to sudden increases in current to be closelymonitored and dynamically adjusted, if necessary or desired.

How the central computer 416 operates to dynamically coordinate PDs inthe electrical distribution system 400 will now be described. Beforedescribing the various operations that the central computer 416 performsin dynamically coordinating the PDs, reference is first made to FIG. 16.FIG. 16 is a drawing shows the time-current characteristic of a PD(assuming a PD constructed like the PD 800 depicted in FIG. 8). The“upper” short-time trip time threshold t_(UPPER) in the time-currentcharacteristics establishes how long the PD 800 will tolerate a loadcurrent higher than the long-time trip threshold current i_(LT) beforethe fault detection and response circuitry 900 of the sense and drivecircuit 816 (see FIG. 9) produces a Gating Disable signal to turn OFFthe PD's 800's solid-state device 806. The “lower” short-time trip timethreshold t_(LOWER) establishes how long the PD 800 will tolerate a loadcurrent just below the instant-trip threshold current i_(MAX). Some orall of these “trip-setting parameters,” t_(UPPER), t_(LOWER), i_(LT),and i_(MAX) for one or more of the PDs 800 (and also possibly thecurrent rating of one or more of the PDs 800 are transmitted to themicrocontrollers 802 of the PDs 800 (over the comm/control bus 414, viathe head-end interface 418, prior to or during the dynamic coordinationprocess described in reference to FIG. 18 below.

To better understand what the dynamic coordination of the PDs entails,reference is also made to FIGS. 17A and 17B, which show the time-currentcharacteristics of PDs (labeled “1” through “5”) involved in a dynamiccoordination. FIG. 17A shows the time-current characteristics of fivePDs labeled “1” through “5” before the coordination, and FIG. 17B showsthe time-current characteristics of the PDs “1” through “5” after thecoordination has been completed. Prior to the coordination beingperformed (FIG. 17A), the PD 800 labeled with a “1” (which maycorrespond to the main PD 408 in the MDP 402 in FIG. 4, for example) isseen to have time-current characteristics that are too close to thetime-current characteristics of the PD 800 labeled with a “2.”Additionally, the time-current characteristics of the PDs 800 labeled“4” and “5” are seen to overlap. Both of these conditions arenon-optimal since either can result in one or more of the PDs 800 nottripping when it/they should or can result in one or more of the PDs 800tripping prematurely when it/they should not. For example theinstant-trip threshold current i_(MAX) and long-time trip thresholdcurrent i_(LT) settings of the PD 800 labeled with a “1” are both likelytoo low. Additionally, the instant-trip threshold current i_(MAX) andlong-time trip threshold current i_(LT) settings of the PD 800 labeledwith a “4” are also too low and/or the instant-trip threshold currenti_(MAX) and long-time trip threshold current i_(LT) settings of the PD800 labeled with a “5” are too high.

Now that the goal of the dynamic coordination process has beendescribed, reference is made to FIG. 18, which is a flowchart thatillustrates one exemplary method 1880 that the microprocessor 1502 ofthe central computer 416 is programmed to follow in dynamicallycoordinating a plurality of PDs in an electrical distribution system, inaccordance with one embodiment of the invention. First, at step 1802 thecentral computer 416 receives real-time sensed current data (andpossibly measured line voltage information) from one or more of the PDs800 over the comm/control bus 414, via the head-end interface 418. Atstep 1804 the central computer 416 then analyzes the received sensedcurrent data, measured voltage data, and possibly retrieves historicaland/or heuristic (i.e., non-real-time) current and/or voltageinformation stored in the central computer's storage 1510. Afteranalyzing the received sensed current data and possible other dateretrieved from the storage 1510, at decision 1806 the central computer416 determines whether there is a coordination problem or othernon-optimal coordination among the various PDs 800 that are beingcoordinated. If a non-optimal coordination is determined not to bepresent, at decision 1808 it is determined whether to continue or endthe method 1800. If it is determined that the method 1800 shouldcontinue, the method 1800 loops back to step 1802. Otherwise, the method1800 ends. If the central computer 416 determines that the PDs 800 arenot optimally coordinated at decision 1806, at decision 1810 the centralcomputer 416 determines whether the non-optimal coordination might becorrectable. If the central computer 416 concludes that the non-optimalcoordination is not correctable, at step 1812 the central computer 416alerts the system user or overseer that it is not able to correct theproblem and the method 1800 ends. However, if the central computer 416determines that the non-optimal coordination might be corrected (“YES”at decision 1810), at step 1814 the central computer 416 computes newtrip-setting parameters for one or more of the PDs 800. Next, at step1816 the central computer 416 transmits the new trip-setting parametersto one or more of the PDs 800 (over the comm/control bus 414 and via thehead-end interface 418), commanding the one or more PDs 800 to adjust tothe newly-computed trip-setting parameters. Once the PDs 800 haveadjusted to the new trip-setting parameters, the central computer 416then performs a system check at step 1818 to determine whether the PDs800 have been properly coordinated (such as in FIG. 17B above). If atdecision 1820 the central computer 416 determines that the PDs 800 havebeen properly coordinated, at step 1822 the central computer 416notifies the system user or overseer that the coordination has beensuccessfully completed. As indicated by decision 1824, the method 1800may then end or it may loop back to step 1802 so that the centralcomputer 416 can monitor the system and re-coordinate in the event thata non-optimal coordination subsequently arises. If at decision 1820 thecentral computer 416 determines that the coordination was unsuccessful,at decision 1826 it is determined whether to continue with anotherattempt to coordinate. If “NO,” at step 1828 the central computer 416alerts the system user or overseer that the coordination could not becompleted. On the other hand, if the central computer 416 determines atdecision 1826 that further adjustment of the trip-setting parametersmight possibly help to optimize the coordination among the PDs 800, atstep 1830 the central computer performs further analysis and computesnew trip-setting parameters for one or more of the PDs 800 once again,and at step 1832 commands the one or more PDs 800 to adjust to the newtrip-setting parameters. Once the PDs 800 have adjusted to the newtrip-setting parameters, the central computer 416 performs a systemcheck at step 1834 to determine whether the PDs 800 have been properlycoordinated. If at decision 1836 it is determined that the coordinationhas been successfully completed, at step 1838 the central computer 416notifies the system user or overseer of the successful coordination.Next, as indicated by decision 1840, the method 1800 may then beterminated or may loop back to step 1802 so that the central computer416 can monitor the system and re-coordinate in the event that anon-optimal coordination arises in the future. On the other hand, if atdecision 1836 the central computer 416 determines that the coordinationwas unsuccessful, at decision 1842 it is determined whether to continuewith another attempt to coordinate. If “NO,” at step 1844 the centralcomputer 416 alerts the system user or overseer that the coordinationcould not be completed and the method 1800 ends. On the other hand, ifthe central computer 416 determines at decision 1842 that furtheradjustment of the trip-setting parameters might possibly help tooptimize the coordination among the PDs 800, the method continues onceagain at step 1830. The central computer 416 may then make furtherattempts to optimize the coordination. If after several attempts, thecoordination is determined not to be possible the system user oroverseer is notified of the inability to complete the coordination andthe method 1800 ends.

In the exemplary method 1800 described above, the central computer 416is programmed so that it performs the dynamic coordination method 1800automatically, upon determining that the PDs in the electricaldistribution system 400 are not optimally coordinated. The centralcomputer 416 can also be programmed to perform the dynamic coordinationmethod 1800 independent of the operational status of the electricaldistribution system, for example, in accordance with a predeterminedpreventative maintenance schedule. In this manner, the central computer416 can maintain optimal coordination among the PDs at all times andre-coordinate when necessary, for example to adapt the coordination tochanging load conditions.

The central computer 416 can also (or alternatively) be programmed sothat it performs the dynamic coordination method 1800 in response to acommand received by a user (e.g., a command entered through the HMI 1506of the central computer 416 by an electrician or other technician) or inresponse to a command received from the system overseer, who or whichmay be an electrical utility or other organization or person having thelegal authority to initiate the dynamic coordination method 1800. Aswill be explained below, the central computer 416 can also (oralternatively) be programmed so that a user of the central computer 416can assist in the coordination and manually adjust or override thetrip-setting parameters of PDs being coordinated.

FIG. 19 is a drawing that illustrates how the panelboard 1400 depictedFIG. 14 can be housed within a panel box 1902. In one embodiment of theinvention the panel box 1902 includes a door 1904 with a window 1906 anda handle or latch 1908 that is used to open and close the door 1904 toaccess the panelboard 1400, reset tripped PDs 800, and performmaintenance and troubleshooting. The head-end interface 418 betweenwhich the comm/control bus 414 and central computer 416 are interfacedmay be located inside the panel box 1502, outside the panel box 1902, orat some remote location. Preferably, the head-end interface 418 islocated near the panel box 1902, however, so that the central computer416 can be easily connected to and interfaced with the comm/control bus414 (e.g., using a USB connector and cable in a situation where thehead-end interface 418 includes a USB-comm/control bus adapter) orwirelessly (e.g., in a situation where the central computer 416 andhead-end interface 418 are both equipped with wireless transceivers(e.g., Wi-Fi transceivers)).

In one embodiment of the invention the panelboard 1400 is furtherequipped with a panel display module that is configured so that it is inelectrical communication with the comm/control bus 414. As illustratedin FIG. 19, the panel display module includes a panel display 1910,which may be: positioned so that it can be displayed through a cut-outin the front face of the panel box 1902 (as in FIG. 19), located insidethe panel box 1902 (e.g., so that it can be viewed through the panel boxdoor window 1906), or mounted outside the panel box 1902 (e.g., affixedto an exterior wall of the panel box 1902). Like the PD displays 514 and814 of the PDs 500 and 800 described above (see FIGS. 5 and 8), thepanel display 1910 is preferably an electronic ink display, so that evenwhen power is removed from the panel display 1901 the information thatit displays continues to be displayed. The panel display 1910 may beconfigured to display any relevant information (real-time ornon-real-time) descriptive of the panelboard 1400. For example, in FIG.19 the panel display 1910 is shown to be displaying the name of thepanelboard 1400 (“Atom Panel 1”), the panelboard from which it is fedpower (“MDP”), the incoming line voltage (“208/120V”), and the maximumcurrent (“225A”) that the panelboard 1400 is able to supply to thevarious loads connected to the panelboard 1400.

As alluded to above, the CRM 1504 of the central computer 416 (see FIG.15) may be configured to store computer program instructions that allowa user of the central computer 416 (e.g., an electrician, engineer orother technician) to interact with the electrical distribution systemand its PDs, for example, the panelboard 1400 and the PDs 800 in thepanel box 1902. Providing this user-interactive capability allows theuser to manually enter, control and even override the trip-settingparameters computed by the central computer 416. In one embodiment ofthe invention, this user-interactive capability is provided in the formof a graphical user interface (GUI). In accordance with this embodimentof the invention, the computer program instructions stored in the CRM1504 of the central computer 416 include instructions that direct themicroprocessor 1502 of the central computer 416 how to generate one ormore GUI pages that are displayed on the central computer's display1508. Preferably, the display 1508 is equipped with touchscreentechnology, which enables the user of the central computer 416 tointeract with the GUI pages by touching the screen of the display 1508or using a stylus. Using simple or multi-touch gesture using one or morefingers, the user can scroll, zoom, input information, etc. and controlwhat GUI pages and content are being displayed on the display 1508. TheGUI and display 1508 could alternatively (or additionally) be configuredso that the user can interact with the GUI pages and content using amouse, touchpad, or other non-touchscreen input device. To facilitateuser-interactivity, the GUI pages preferably include icons and widgets,such as radio buttons, sliders, spinners, drop-down lists, menus, comboand text boxes, scrollbars, etc.

FIG. 20 is a drawing depicting how one of the GUI pages generated by thecentral computer 416 (which in this case comprises a tablet computer)may comprise a one-line GUI page 2002 that displays the panelboards inan electrical distribution system. The one-line GUI page shows that theelectrical distribution system that the tablet computer is connected to(via the comm/control bus 414) comprises an MDP (GUI element 2004labeled “Panel MDP”) fed from an electrical utility (GUI element 2006)and a downstream sub-panelboard (GUI element 2008 labeled “Panel HVAC”).The MDP and sub-panelboard GUI elements 2004 and 2008 further displaythe line voltages and maximum current that the MDP and sub-panelboardare able to supply to their respective loads.

Each of the MDP and sub-panelboard GUI elements 2004 and 2008 in theone-line GUI page shown in FIG. 20 may be a user-interactive button,which the user of the central computer 416 can touch to open a panel GUIpage showing how various PDs 800 in the selected MDP or sub-panelboardare configured. FIG. 21 illustrates, for example, a panel GUI page 2102that is generated by the central computer 416 and displayed on thecentral computer's display 1508 after the user has touched thesub-panelboard GUI element 2088 in the one-line GUI page 2002. Inaddition to displaying images 2104 of the various PDs configured in theselected sub-panelboard, the panel GUI page 2102 includes load-namelabels that identify the loads being protected by the various PDs in thesub-panelboard. Images of what is presently being displayed on the PDsdisplays (e.g., PD display 814 in FIG. 12) and on the panel display 1910(see FIG. 19) may also be displayed in the panel GUI page 2102.

In accordance with one embodiment of the invention, the GUI computerprogram instructions stored in the CRM 1504 of the central computer 416further include user-interactive instructions that provide the user ofthe central computer 416 the ability to change the information that isdisplayed by the electronic ink displays of the PDs (e.g., PD display814 in FIG. 12) and/or the information that is being displayed by theelectronic ink panel display 1910 (see FIG. 19). FIG. 22 is a flowchartthat illustrates a method 2200 that the central computer 416 isprogrammed to follow in allowing the user to update this displayinformation. Note that only salient steps in the method 2200 arepresented in the flowchart, and the various steps and decisions in theflowchart are not necessarily performed in the order shown or as asequence of discrete events. For example, some of the steps anddecisions may be performed continuously and some of the steps anddecisions may be performed simultaneously. First, at step 2202 thecentral computer 416 directs the display 1508 of the central computer todisplay the panel GUI page 2102 (FIG. 21) to the user. Next, at decision2204 the central computer 416 determines whether the user has entered acommand indicating that the user wishes to update information beingdisplayed on the panel display 1910. If the central computer 416determines that the user has input a command to update the informationbeing displayed by the panel display 1910, at step 2206 the centralcomputer 416 then receives updated panel display information from theuser. The updated panel display information may be entered by the userusing a physical keyboard, if the central computer 416 is equipped witha physical keyboard. Alternatively, the panel display element 2106 inthe panel GUI page 2102 (see FIG. 21) can be programmed to serve as auser-interactive button, which when touched by the user opens up auser-interactive text box and virtual keyboard that the user caninteract with to enter the user's desired panel display information.After receiving the updated panel display information from the user, thecentral computer 416 responds at step 2208 by refreshing and updatingthe panel display 1910 accordingly. At decision 2210 the centralcomputer 416 then determines whether the user has entered a commandindicating that the user wishes to update information being displayed bythe electronic ink display(s) of one or more of the PDs. If the centralcomputer 416 determines that the user has input a command to update theinformation being displayed by the electronic ink displays of one ormore of the PDs, at step 2212 the central computer 416 then receives theupdated PD display information from the user. Again, the updated PDdisplay information may be entered by the user using a physicalkeyboard, if the central computer 416 is equipped with a physicalkeyboard. Alternatively, the PD images 2104 displayed on the panel GUIpage 2102 (see FIG. 21) can be programmed to serve as user-interactivebuttons, which when touched by the user opens up a user-interactive textbox and virtual keyboard that the user can interact with to enter theupdated PD display information for the one or more PDs. Finally, afterreceiving the updated PD display information, at step 2214 the centralcomputer communicates the updated PD display information to theappropriate microcontrollers 802 of the PDs (over the comm/control busand via the head-end interface 418), so that the microcontrollers 802can then update their electronic ink displays accordingly. (Note if thenames of any of the loads of any of the PD electronic displays have beenupdated, the central computer 416 automatically updates the load-namelabels next to the corresponding images 2104 of the PDs in the panel GUIpage (see FIG. 21).)

In the exemplary dynamic coordination method 1900 described above (seeFIG. 19 and accompanying description), the central computer 416 isprogrammed so that it dynamically coordinates PDs in an electricaldistribution system automatically, i.e., without the need for any userassistance. In some circumstances, for example, if the central computer416 is unable to complete a successful coordination, it may be desirableor necessary for an electrician, engineer or other technician tomanually coordinate the PDs or override the trip-setting parameters thatthe central computer 416 computes, in order to complete a successfulcoordination. To support this ‘user-assisted’ dynamic coordination, theGUI program instructions stored in the central computer's CRM 1504 andexecuted by the microprocessor 1502 of the central computer 416 mayfurther include instructions that direct the central computer 416 togenerate and display a dynamic coordination GUI page 2302, such asillustrated in FIG. 23. The dynamic coordination GUI page 2302preferably includes a time-current coordination overlay 2304 thatdisplays the time-current characteristics of the PDs being manuallycoordinated. In the exemplary dynamic coordination overlay 2304 shown inFIG. 23, time-current characteristics of five PDs are shown. The fivePDs are labeled “1,” “2,” “3,” “4” and “5.” However, in a preferredembodiment, each of the time-current characteristic lines has a uniquecolor, so that they are distinguished by different colors rather than bynumbers, and the legend in the coordination overlay 2304 that identifiesthe time-current characteristic lines also uses corresponding andmatching colors. Each of the time-current characteristic lines alsoserves as a user-interactive button, which when touched by the usercauses the central computer 416 to display the trip-setting parametersof the selected PD on the dynamic coordination GUI page 2302, includingthe long-time trip threshold long-time trip threshold current i_(LT),short-time trip time threshold t_(UPPER), and instant-trip thresholdcurrent i_(MAX) (see FIG. 16). In the snapshot of the dynamiccoordination GUI page 2302 shown in FIG. 23, the PD that is selected isPD #2, which is the main PD in a panelboard having the name “PanelHVAC,” as shown in the text box with the label “Name=” in the upper leftcorner of the dynamic coordination GUI page 2302. The dynamiccoordination GUI page 2302 further includes sliders 2306 that the usercan touch and slide to manually change the long-time trip thresholdcurrent i_(LT), short-time trip time threshold t_(UPPER), andinstant-trip threshold current i_(MAX) of the selected PD. (Although notshown, a slider can also be included for adjusting the short-time triptime threshold t_(LOWER).) Further displayed on the dynamic coordinationGUI page 2302 is the current rating of the selected PD. As shown, the PDthat is currently selected has a current rating of 100A. Note that theName and Rating of the selected PD can also be changed by entering thedesired change in Name and/or Rating in the text boxes with the “Name=”and “Rating=” labels. Also included in the dynamic coordination GUI page2302 is a table 2308 that displays real-time metering information of theselected PD, including real-time voltage, real-time amperage, real-timekilowatts and real-time temperature. Finally, the dynamic coordinationGUI page 2302 includes user-interactive “CLOSE,” “OPEN,” “COORDINATION”and “APPLY” buttons. The “OPEN” and “CLOSE” buttons are user-interactivebuttons that allow the user to remotely deactivate (i.e., turn OFF) thesolid-state device of the selected PD (to “open” the selected PD's loadcircuit) and remotely activate (i.e., turn ON) the solid-state device ofthe selected PD (to “close” the selected PD's load circuit). The “APPLY”button is a user-interactive button that is used by the user to directthe central computer to apply any changes the user has entered throughthe dynamic coordination GUI page 2302, including any changes made tothe trip-setting parameters of a selected PD via the sliders 2306, anychanges the user has entered in the “Name=” and “Rating=” text boxes ofa selected PD, etc. Finally, the “COORDINATE” button is auser-interactive button that is used by the user to request the centralcomputer to coordinate the various PDs represented in the coordinationoverlay 2304, once the user has completed individually adjusting thetrip-setting parameters of one or more of the PDs.

FIG. 24 is a flowchart that illustrates a method 2400 the centralcomputer 416 performs when a user is interacting with the dynamiccoordination GUI page 2302 to manually coordinate a plurality of PDs.Note that the steps and decisions represented in the flowchart are notnecessarily performed in the order shown, and some steps and decisionsmay be performed continuously or simultaneously, as will be appreciatedby those of ordinary skill in the art. At step 2402 in the method 2400the central computer 416 receives real-time sense current data (andpossibly also real-time voltage information) from the PDs that are beingcoordinated. After receiving the current and/or voltage information fromthe PDs, at step 2404 the central computer generates and displays thedynamic coordination GUI page 2302 on its display 1508, including thetime-current characteristics of all PDs that are going to be manuallycoordinated and some or all of the other elements and controls of theexemplary dynamic coordination GUI page 2302 depicted in FIG. 23. (Notethat in displaying the time-current characteristics the trip-settingparameters of the various PDs are also received from the PDs or areretrieved from the storage unit 1510.) Next, at step 2406 the centralcomputer 416 receives a command from the user indicating that the userhas selected one of the PDs for adjustment. Responding to the usercommand, at step 2408 the central computer 416 then updates the dynamiccoordination GUI page 2302 so that the Name, Rating, trip-settingparameters of the selected PD (long-time trip threshold long-time tripthreshold current i_(LT), short-time trip time threshold t_(UPPER), andinstant-trip threshold current i_(MAX)), and real-time metering table2308 are displayed. Next, at step 2410 the central computer 2410receives updated trip-setting parameters from the user, which the userinputs by adjusting the sliders 2306 of the selected PD and commands thecentral computer to accept by touching the “APPLY” button. At decision2412 the central computer then determines whether the user has selectedanother PD to adjust. If “YES” the method 2400 loops back to step 2406where the central computer 416 waits to receive PD selection andtrip-setting parameter adjustments for other of the PDs in thecoordination overlay 2304. After all trip-setting adjustments have beeninput by the user, the user then touches the “COORDINATE” button,requesting that the central computer 416 coordinate the PDs accordingly.After receiving the COORDINATION request, at step 2414 the centralcomputer 416 determines at decision 2416 whether the user's coordinationrequest might pose a hazard or other problem. If a hazard or otherproblem might possibly occur if the coordination is made as directed bythe user, at step 2418 the coordination request is denied, and at step2420 the central computer presents an error message on the dynamiccoordination GUI page 2302 (and possibly alerts the user with an audiblewarning) that the coordination request could not be accepted. If, on theother hand, the central computer 416 determines that the coordinationrequest is acceptable, at step 2422 the central computer 416 transmits(over the comm/control bus 414 and via the head-end interface 418) theuser-set trip-setting parameters to the PDs that are being coordinated.Finally, after the PDs have adjusted to the user-set trip-settingparameters, at step 2444 the central computer 416 updates thecoordination overlay 2304 image on the dynamic coordination GUI page2302 and displays a message to the user that the coordination has beensuccessfully completed.

While various embodiments of the present invention have been described,they have been presented by way of example and not limitation. It willbe apparent to persons skilled in the relevant art that various changesin form and detail may be made to the exemplary embodiments withoutdeparting from the true spirit and scope of the invention. Accordingly,the scope of the invention should not be limited by the specifics of theexemplary embodiments but, instead, should be determined by the appendedclaims, including the full scope of equivalents to which such claims areentitled.

The invention claimed is:
 1. A dynamically coordinatable electricaldistribution system, comprising: a plurality of protection devices (PDs)configured to protect a plurality of electrical loads from exceedinglyhigh overcurrent conditions, each of the PDs having line-in and line-outterminals with a solid-state device coupled between the line-in andline-out terminals and electrically adjustable time-currentcharacteristics; a communications and control (comm/control) buscommunicatively coupled to the plurality of PDs; and a central computerconfigured to communicate with the plurality of PDs via the comm/controlbus, receive sensed current data from the plurality of PDs via thecomm/control bus, automatically determine, without any humaninvolvement, whether the electrically adjustable time-currentcharacteristics of the plurality of PDs are optimally coordinated, anddynamically coordinate the electrically adjustable time-currentcharacteristics of the plurality of PDs if it is determined that theelectrically adjustable time-current characteristics of the plurality ofPDs are not optimally coordinated.
 2. The dynamically coordinatableelectrical distribution system of claim 1, wherein the central computerincludes a processor, a display, and a computer-readable medium (CRM)configured to store computer program instructions that the processorexecutes to generate and present a user-interactive graphical userinterface (GUI) on the display.
 3. The dynamically coordinatableelectrical distribution system of claim 2, wherein the user-interactiveGUI includes a one-line GUI page that displays a one-line depiction ofthe dynamically coordinatable electrical distribution system or aone-line depiction of a portion or section of the dynamicallycoordinatable electrical distribution system.
 4. The dynamicallycoordinatable electrical distribution system of claim 2, wherein theuser-interactive GUI includes a user-interactive panel GUI page thatdisplays user-interactive controls and a depiction of a panelboard,which some or all of the plurality of PDs are electrically connected to.5. The dynamically coordinatable electrical distribution system of claim2, wherein the user-interactive GUI includes user-interactive controlsthat a user can manipulate to set or change information displayed onelectronic displays of the plurality of PDs.
 6. The dynamicallycoordinatable electrical distribution system of claim 2, wherein theuser-interactive GUI includes user-interactive controls that a user canmanipulate to set or change information displayed on an electronic paneldisplay of a panelboard that some or all of the plurality of PDs areelectrically connected to.
 7. The dynamically coordinatable electricaldistribution system of claim 2, wherein the user-interactive GUIincludes user-interactive controls that allow a user to inputtrip-setting parameters that the central computer transmits, via thecomm/control bus, to one or more PDs of the plurality of PDs, tocoordinate the time-current characteristics of the plurality of PDs. 8.The dynamically coordinatable electrical distribution system of claim 2,wherein the user-interactive GUI comprises a time-currentcharacteristics page that displays time-current characteristicinformation of one or more PDs of the plurality of PDs.
 9. Thedynamically coordinatable electrical distribution system of claim 8,wherein the time-current characteristics page includes user-interactivecontrols that allow a user to set or change the time-currentcharacteristic information of the one or more PDs of the plurality ofPDs.
 10. The dynamically coordinatable electrical distribution system ofclaim 8, wherein the time-current characteristic information is depictedin a form of a time-current characteristics graph.
 11. The dynamicallycoordinatable electrical distribution system of claim 10, wherein thetime-current characteristic page displays time-current characteristiccurves of two or more PDs before coordination and the central computeris programmed to update the time-current characteristic page to displaythe time-current characteristic curves of the two or more PDs after thecoordination.
 12. The dynamically coordinatable electrical distributionsystem of claim 10, wherein the user-interactive GUI includesuser-interactive controls that allow a user to manipulate time-currentcharacteristic curves being displayed in the time-currentcharacteristics graph.
 13. The dynamically coordinatable electricaldistribution system of claim 2, wherein the user-interactive GUIincludes user-interactive controls that allow a user to override thedynamic coordination of the plurality of PDs and manually coordinate theplurality of PDs.
 14. An apparatus, comprising: a computer including adisplay and a processor adapted to electrically communicate with aplurality of intelligently-controlled protection devices (PDs) in anelectrical distribution system yia a communications and control(comm/control) bus, each of the intelligently-controlled PDs including:line-in and line-out terminals with a solid-state device coupled betweenthe line-in and line out terminals, electrically adjustable time-currentcharacteristics, and a microcontroller configured to adjust theelectrically adjustable time-current characteristics; and acomputer-readable memory coupled to the processor having computerprogram instructions stored thereon, which when executed by theprocessor cause the processor to: automatically determine, without anyhuman involvement, whether the electrically adjustable time-currentcharacteristics of any two or more of the intelligently-controlled PDsoverlap, and upon determining that the electrically adjustabletime-current characteristics of two or more of theintelligently-controlled PDs overlap, dynamically coordinate theplurality of intelligently-controlled PDs, wherein the processordetermines whether the electrically adjustable time-currentcharacteristics of any two or more intelligently-controlled PDs of theplurality of intelligently-controlled PDs overlap based on sensedcurrent data received from the microcontrollers of the plurality ofintelligently-controlled PDs via the comm/control bus, and the processordynamically coordinates the plurality of intelligently-controlled PDsby: computing trip-setting parameters for one or more of theintelligently-controlled PDs, transmitting the trip-setting parametersto the one or more of the intelligently-controlled PDs, via thecomm/control bus, and commanding the microcontroller(s) in the one ormore of the intelligently-controlled PDs to adjust to the trip-settingparameters.
 15. The apparatus of claim 14, wherein the computer programinstructions further include instructions, which, when executed by theprocessor, cause the processor to generate and present auser-interactive graphical user interface (GUI) on the computer'sdisplay.
 16. The apparatus of claim 15, wherein the user-interactive GUIincludes a one-line GUI page that displays a one-line depiction of theelectrical distribution system or a one-line depiction of a portion orsection of the electrical distribution system.
 17. The apparatus ofclaim 15, wherein the user-interactive GUI includes user-interactivecontrols that allow a user to input user-defined trip-setting parametersfor one or more of the intelligently-controlled PDs.
 18. The apparatusof claim 15, wherein the user-interactive GUI comprises a time-currentcharacteristics page that displays time-current characteristicinformation of one or more of the intelligently-controlled PDs.
 19. Theapparatus of claim 18, wherein the time-current characteristics pageincludes user-interactive controls that allow a user to set or changethe time-current characteristic information of the one or moreintelligently-controlled PDs.
 20. The apparatus of claim 18, wherein thetime-current characteristic information is depicted in a form of atime-current characteristics graph.
 21. The apparatus of claim 20,wherein the time-current characteristic page displays time-currentcharacteristic curves of two or more intelligently-controlled PDs beforecoordination and the processor is programmed to update the time-currentcharacteristic page to display the time-current characteristic curves ofthe two or more intelligently-controlled PDs after the coordination. 22.The apparatus of claim 20, wherein the user-interactive GUI includesuser-interactive controls that allow a user to manipulate thetime-current characteristic curves being displayed in the time-currentcharacteristics graph.
 23. The apparatus of claim 15, wherein theuser-interactive GUI includes user-interactive controls that allow auser to manually coordinate and override the dynamic coordination of theplurality of intelligently-controlled PDs.